组合返回和切换

问题描述

如何组合 return 和 switch case 语句?

How can I combine return and switch case statements?

我想要类似的东西

return switch(a)
       {
          case 1:"lalala"
          case 2:"blalbla"
          case 3:"lolollo"
          default:"default" 
       };

我知道这个解决方案

switch(a)
{
    case 1: return "lalala";
    case 2: return "blalbla";
    case 3: return "lolollo";
    default: return "default";
}

但我只想使用 return 运算符.

But I want to only use the return operator.

推荐答案

注意:从 C#8 开始(十年后！)现在可以实现了，请看答案 下方.

Note: As of C#8 (ten years later!) this is now possible, please see the answer below.

switch 和 return 不能这样组合，因为 switch 是一个 statement，而不是 表达式(即不返回值).
如果你真的想只使用一个 return，你可以制作一个 Dictionary 来将 switch 变量映射到返回值:

switch and return can't combine that way, because switch is a statement, not an expression (i.e., it doesn't return a value).
If you really want to use just a single return, you could make a Dictionary to map the switch variable to return values:

var map = new Dictionary<int, string>() 
{
    {1, "lala"}, 
    {2, "lolo"}, 
    {3, "haha"}, 
};
string output;
return map.TryGetValue(a, out output) ? output : "default";

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